Commit Graph

20 Commits

Author SHA1 Message Date
Paulo Alcantara (SUSE)
bacd704a95 cifs: handle prefix paths in reconnect
For the case where we have a DFS path like below and we're currently
connected to targetA:

    //dfsroot/link -> //targetA/share/foo, //targetB/share/bar

after failover, we should make sure to update cifs_sb->prepath so the
next operations will use the new prefix path "/bar".

Besides, in order to simplify the use of different prefix paths,
enforce CIFS_MOUNT_USE_PREFIX_PATH for DFS mounts so we don't have to
revalidate the root dentry every time we set a new prefix path.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Acked-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-03-22 22:49:09 -05:00
Alexey Dobriyan
97a32539b9 proc: convert everything to "struct proc_ops"
The most notable change is DEFINE_SHOW_ATTRIBUTE macro split in
seq_file.h.

Conversion rule is:

	llseek		=> proc_lseek
	unlocked_ioctl	=> proc_ioctl

	xxx		=> proc_xxx

	delete ".owner = THIS_MODULE" line

[akpm@linux-foundation.org: fix drivers/isdn/capi/kcapi_proc.c]
[sfr@canb.auug.org.au: fix kernel/sched/psi.c]
  Link: http://lkml.kernel.org/r/20200122180545.36222f50@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191225172546.GB13378@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-02-04 03:05:26 +00:00
Chen Zhou
050d2a8b69 cifs: use PTR_ERR_OR_ZERO() to simplify code
PTR_ERR_OR_ZERO contains if(IS_ERR(...)) + PTR_ERR, just use
PTR_ERR_OR_ZERO directly.

Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
2020-01-26 19:24:17 -06:00
Steve French
463a7b457c cifs: fix unitialized variable poential problem with network I/O cache lock patch
static analysis with Coverity detected an issue with the following
commit:

 Author: Paulo Alcantara (SUSE) <pc@cjr.nz>
 Date:   Wed Dec 4 17:38:03 2019 -0300

    cifs: Avoid doing network I/O while holding cache lock

Addresses-Coverity: ("Uninitialized pointer read")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
YueHaibing
eecfc57130 cifs: Fix return value in __update_cache_entry
copy_ref_data() may return error, it should be
returned to upstream caller.

Fixes: 03535b72873b ("cifs: Avoid doing network I/O while holding cache lock")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
742d8de018 cifs: Avoid doing network I/O while holding cache lock
When creating or updating a cache entry, we need to get an DFS
referral (get_dfs_referral), so avoid holding any locks during such
network operation.

To prevent that, do the following:
* change cache hashtable sync method from RCU sync to a read/write
  lock.
* use GFP_ATOMIC in memory allocations.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
06d57378bc cifs: Fix potential deadlock when updating vol in cifs_reconnect()
We can't acquire volume lock while refreshing the DFS cache because
cifs_reconnect() may call dfs_cache_update_vol() while we are walking
through the volume list.

To prevent that, make vol_info refcounted, create a temp list with all
volumes eligible for refreshing, and then use it without any locks
held.

Besides, replace vol_lock with a spinlock and protect cache_ttl from
concurrent accesses or changes.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
ff2f7fc082 cifs: Merge is_path_valid() into get_normalized_path()
Just do the trivial path validation in get_normalized_path().

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
345c1a4a9e cifs: Introduce helpers for finding TCP connection
Add helpers for finding TCP connections that are good candidates for
being used by DFS refresh worker.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
199c6bdfb0 cifs: Get rid of kstrdup_const()'d paths
The DFS cache API is mostly used with heap allocated strings.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
185352ae61 cifs: Clean up DFS referral cache
Do some renaming and code cleanup.

No functional changes.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2020-01-26 19:24:16 -06:00
Paulo Alcantara (SUSE)
df3df923b3 cifs: Fix lookup of root ses in DFS referral cache
We don't care about module aliasing validation in
cifs_compose_mount_options(..., is_smb3) when finding the root SMB
session of an DFS namespace in order to refresh DFS referral cache.

The following issue has been observed when mounting with '-t smb3' and
then specifying 'vers=2.0':

...
Nov 08 15:27:08 tw kernel: address conversion returned 0 for FS0.WIN.LOCAL
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_query((null),FS0.WIN.LOCAL,13,(null))
Nov 08 15:27:08 tw kernel: [kworke] call request_key(,FS0.WIN.LOCAL,)
Nov 08 15:27:08 tw kernel: [kworke] ==> dns_resolver_cmp(FS0.WIN.LOCAL,FS0.WIN.LOCAL)
Nov 08 15:27:08 tw kernel: [kworke] <== dns_resolver_cmp() = 1
Nov 08 15:27:08 tw kernel: [kworke] <== dns_query() = 13
Nov 08 15:27:08 tw kernel: fs/cifs/dns_resolve.c: dns_resolve_server_name_to_ip: resolved: FS0.WIN.LOCAL to 192.168.30.26
===> Nov 08 15:27:08 tw kernel: CIFS VFS: vers=2.0 not permitted when mounting with smb3
Nov 08 15:27:08 tw kernel: fs/cifs/dfs_cache.c: CIFS VFS: leaving refresh_tcon (xid = 26) rc = -22
...

Fixes: 5072010ccf ("cifs: Fix DFS cache refresher for DFS links")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-11-25 09:25:32 -06:00
Kefeng Wang
06f2fca7ff fs: cifs: Drop unlikely before IS_ERR(_OR_NULL)
IS_ERR(_OR_NULL) already contain an 'unlikely' compiler flag,
so no need to do that again from its callers. Drop it.

Cc: linux-cifs@vger.kernel.org
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
2019-07-07 22:37:42 -05:00
Gen Zhang
50fbc13dc1 dfs_cache: fix a wrong use of kfree in flush_cache_ent()
In flush_cache_ent(), 'ce->ce_path' is allocated by kstrdup_const().
It should be freed by kfree_const(), rather than kfree().

Signed-off-by: Gen Zhang <blackgod016574@gmail.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-05-28 19:13:58 -05:00
Paulo Alcantara (SUSE)
5072010ccf cifs: Fix DFS cache refresher for DFS links
As per MS-DFSC, when a DFS cache entry is expired and it is a DFS
link, then a new DFS referral must be sent to root server in order to
refresh the expired entry.

This patch ensures that all new DFS referrals for refreshing the cache
are sent to DFS root.

Signed-off-by: Paulo Alcantara (SUSE) <paulo@paulo.ac>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-05-07 23:24:54 -05:00
Dan Carpenter
c715f89c4d cifs: Fix a tiny potential memory leak
The most recent "it" allocation is leaked on this error path.  I
believe that small allocations always succeed in current kernels so
this doesn't really affect run time.

Fixes: 54be1f6c1c ("cifs: Add DFS cache routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2019-01-10 14:32:30 -06:00
Dan Carpenter
34bca9bbe7 cifs: Use kzfree() to free password
We should zero out the password before we free it.

Fixes: 3d6cacbb5310 ("cifs: Add DFS cache routines")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
2018-12-28 10:09:46 -06:00
Wei Yongjun
3e80be0158 cifs: Fix to use kmem_cache_free() instead of kfree()
memory allocated by kmem_cache_alloc() in alloc_cache_entry()
should be freed using kmem_cache_free(), not kfree().

Fixes: 34a44fb160f9 ("cifs: Add DFS cache routines")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
2018-12-28 10:09:46 -06:00
Stephen Rothwell
54e4f73cbe cifs: update for current_kernel_time64() removal
Fixes cifs build failure after merge of the y2038 tree

After merging the y2038 tree, today's linux-next build (x86_64
allmodconfig) failed like this:

fs/cifs/dfs_cache.c: In function 'cache_entry_expired':
fs/cifs/dfs_cache.c:106:7: error: implicit declaration of function 'current_kernel_time64'; did you mean 'core_kernel_text'? [-Werror=implicit-function-declaration]
  ts = current_kernel_time64();
       ^~~~~~~~~~~~~~~~~~~~~
       core_kernel_text
fs/cifs/dfs_cache.c:106:5: error: incompatible types when assigning to type 'struct timespec64' from type 'int'
  ts = current_kernel_time64();
     ^
fs/cifs/dfs_cache.c: In function 'get_expire_time':
fs/cifs/dfs_cache.c:342:24: error: incompatible type for argument 1 of 'timespec64_add'
  return timespec64_add(current_kernel_time64(), ts);
                        ^~~~~~~~~~~~~~~~~~~~~~~
In file included from include/linux/restart_block.h:10,
                 from include/linux/thread_info.h:13,
                 from arch/x86/include/asm/preempt.h:7,
                 from include/linux/preempt.h:78,
                 from include/linux/rcupdate.h:40,
                 from fs/cifs/dfs_cache.c:8:
include/linux/time64.h:66:66: note: expected 'struct timespec64' but argument is of type 'int'
 static inline struct timespec64 timespec64_add(struct timespec64 lhs,
                                                ~~~~~~~~~~~~~~~~~~^~~
fs/cifs/dfs_cache.c:343:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

Caused by:

  commit ccea641b6742 ("timekeeping: remove obsolete time accessors")

interacting with:
  commit 34a44fb160f9 ("cifs: Add DFS cache routines")

from the cifs tree.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Paulo Alcantara <palcantara@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
2018-12-28 10:09:46 -06:00
Paulo Alcantara
54be1f6c1c cifs: Add DFS cache routines
* Add new dfs_cache.[ch] files

* Add new /proc/fs/cifs/dfscache file
  - dump current cache when read
  - clear current cache when writing "0" to it

* Add delayed_work to periodically refresh cache entries

The new interface will be used for caching DFS referrals, as well as
supporting client target failover.

The DFS cache is a hashtable that maps UNC paths to cache entries.

A cache entry contains:
- the UNC path it is mapped on
- how much the the UNC path the entry consumes
- flags
- a Time-To-Live after which the entry expires
- a list of possible targets (linked lists of UNC paths)
- a "hint target" pointing the last known working target or the first
  target if none were tried. This hint lets cifs.ko remember and try
  working targets first.

* Looking for an entry in the cache is done with dfs_cache_find()
  - if no valid entries are found, a DFS query is made, stored in the
    cache and returned
  - the full target list can be copied and returned to avoid race
    conditions and looped on with the help with the
    dfs_cache_tgt_iterator

* Updating the target hint to the next target is done with
  dfs_cache_update_tgthint()

These functions have a dfs_cache_noreq_XXX() version that doesn't
fetches referrals if no entries are found. These versions don't
require the tcp/ses/tcon/cifs_sb parameters as a result.

Expired entries cannot be used and since they have a pretty short TTL
[1] in order for them to be useful for failover the DFS cache adds a
delayed work called periodically to keep them fresh.

Since we might not have available connections to issue the referral
request when refreshing we need to store volume_info structs with
credentials and other needed info to be able to connect to the right
server.

1: Windows defaults: 5mn for domain-based referrals, 30mn for regular
links

Signed-off-by: Paulo Alcantara <palcantara@suse.de>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2018-12-28 10:05:58 -06:00